With the proliferation of a wide variety of microprocessor-and computer-controlled equipment there has arisen a need for correspondingly complex test and diagnostic equipment. More specifically, equipment from appliances to automobiles, elevators to automatic teller machines, building HVAC equipment to gasoline pumps, and of course a wide variety of computer and communication equipment per se, is now provided with unprecedented functionality through extensive use of complex electronics, particularly microprocessors. Testing such complex equipment requires correspondingly sophisticated test equipment.
While the specific test methodology to be employed varies widely, in general a test instrument specialized to the equipment to be tested is connected thereto by way of a physical interface, such that a microprocessor of the test instrument is in signal-communicating relation to the circuitry of the equipment. Appropriate test conditions are then created--for example, in testing an automatic teller machine, the test technician might simulate a particular type of transaction--and the test instrument will monitor the response of the equipment. In the telecommunication connection, the testing may involve monitoring ongoing traffic; injection of predetermined test messages, to monitor the system's response; measuring operational parameters, such as bit error rates, message travel times and the like; or monitoring the operation of individual components of the system.
As noted, as a rule the test instrument employed for testing given equipment is specialized thereto, that is, is useful only for testing a specific type of equipment or perhaps a class of related equipment. Automobile manufacturers, for example, provide their dealers and authorized repair shops with new computers for testing and diagnosing the engine management systems of each new class of cars, i.e., as the electronics of each new generation of cars become more sophisticated, the dealers must upgrade their computers accordingly. Moreover, each manufacturer employs a unique format not only for the physical interface, but also for the data formats used, the microprocessor architecture, and so on, so that each instrument is usable only with a single manufacturer's vehicles.
In general, such test instruments comprise a user interface for communicating information to and receiving instructions from the technician. Information is usually communicated to the user by way of a display screen; input may be accomodated by way of a keyboard or keypad, by the user's scrolling along a list of possible choices, by pointing to a specific region on a graphical user interface (GUI) with a "mouse", "trackball", or other pointing device, or, if the display is touch-sensitive, by simply contacting the defined regions. In most cases, the user interface is designed to "prompt" the user through an appropriate sequence of "screens" so as to select a particular test to be performed, determine various parameters, control the disposition of the results, and the like.
It has not escaped the attention of the art that despite their wide variety, most such test instruments have many common physical features, and that they differ principally in the physical interface used to make the connection to the equipment under test and in the software required to perform the test and to define the user interface. In particular, the art has recognized that substantial savings could be realized if a common unit, including generic components such as a display screen, power supply, and user input interface, could be "customized" for a particular application by addition thereto of physical interface hardware and internal and user interface software.
For example, a number of devices have been offered for telecommunications testing wherein a basic unit is "customized" for testing devices obeying varying protocols. Here the basic units have typically been "laptop" personal computers adapted for testing of particular devices by plug-in memory cards and/or supply of floppy disks providing the corresponding software. Such plug-in cards are normally rather delicate, and the floppy disks are susceptible of loss or physical damage. See generally U.S. Pat. No. 5,121,342 to Symborski; Schillaci et al U.S. Pat. No. 5,583,912; Horton et al U.S. Pat. No. 5,533,093; Selig et al U.S. Pat. No. 5,521,958; and Heins U.S. Pat. No. 5,528,660.
U.S. Pat. Nos. 5,432,705 and 5,511,108, both to Severt et al, show an "administrative computer" for storing work order information, customer addresses and the like, and which can be coupled to test equipment for recording test results. In a second embodiment of this device, shown in the '108 patent, the administrative computer is divided into two mating portions 402 and 404 and a "slice" 438 can be inserted and assembled therebetween. See FIGS. 12, 13, and 24 of the '108 patent, and the specification at cols. 9-12. As discussed at col. 9, line 44, the slice "contains circuitry and devices to facilitate testing, maintaining or installing telephone lines or equipment." The slice includes the physical connection to the circuit to be tested; see FIG. 18 and the specification at col. 11, lines 1-5.
The '108 patent states explictly that other types of slice could be provided for testing equipment other than telephone equipment per se, such as "fiber optic systems, . . . non-telephone communications systems . . . for supporting general field servicing of electrical devices, e.g., copiers, printers, computers, faxes and the like . . . Although only one slice is provided in the depicted embodiment, it is possible to configure a computer to accomodate more than one slice, to provide a plurality of capabilities . . . Slices can also be provided which enhance the capabilities of the basic computer . . . such as . . . additional memory, co-processing capabilities, networking capabilities or the like." Col. 23, lines 39-56.
The device shown in the '108 Severt et al patent is essentially a complete computer that can be adapted for any of a variety of specific uses by assembly of a particular slice. This is evidently not intended to be performed repetitively; note the complicated assembly arrangements shown by FIG. 24. It is therefore clear when the slice has been assembled, the unit has essentially been dedicated to the particular use. This significantly limits the utility of the device; for example, there are numerous occasions in the telecommunication industry at which two different types of communications systems meet, as where a satellite "downlink" is interfaced to a land line. It would be highly desirable to provide a technician with a single instrument capable of ready and convenient adaptation to testing both types of equipment.
Other generally relevant patents can be summarized as follows:
Debacker U.S. Pat. No. 5,608,644 shows a simulator and method for testing system software of a communication system. The software employed is divided into "program modules" for testing various system functions.
Dariano U.S. Pat. No. 5,173,896 shows a T-Carrier Network Simulator for training technicians by simulating various network faults. It appears that various faults are simulated by plugging "smart jacks" emulating various circuit characteristics into the simulator.
Butler et al U.S. Pat. No. 5,377,259 shows a data terminal for field use by technicians capable of downloading software, work orders, and the like from a host computer over a normal telephone line. Various communication protocols are stored by the unit. Additional Butler U.S. Pat. Nos. 4,837,811 and 4,922,515 are generally similar.
Dack et al U.S. Pat. No. 4,996,695 shows a test device for testing circuits in which a shift register is provided to compensate for delays introduced in testing.
Fitch U.S. Pat. No. 5,557,539 shows an instrument for testing voice mail systems. A memory stores a number of test procedures.
Jablway et al U.S. Pat. No. 4,536,703 shows test instruments for detecting shorts and opens in multiple wire sets. Two instruments at spaced locations may be used simultaneously.
Harris et al U.S. Pat. No. 3,956,601 shows use of paired telecommunications analyzers at opposite ends of a connection. One inserts a predetermined test signal, and the other detects the signal.